EP0797188A1 - Magnetkopf mit starker Reluktanz - Google Patents

Magnetkopf mit starker Reluktanz Download PDF

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Publication number
EP0797188A1
EP0797188A1 EP97400295A EP97400295A EP0797188A1 EP 0797188 A1 EP0797188 A1 EP 0797188A1 EP 97400295 A EP97400295 A EP 97400295A EP 97400295 A EP97400295 A EP 97400295A EP 0797188 A1 EP0797188 A1 EP 0797188A1
Authority
EP
European Patent Office
Prior art keywords
magnetic
layer
concentrators
pole pieces
magnetic head
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97400295A
Other languages
English (en)
French (fr)
Inventor
Jean-Pierre Lazzari
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Silmag SA
Original Assignee
Silmag SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Silmag SA filed Critical Silmag SA
Publication of EP0797188A1 publication Critical patent/EP0797188A1/de
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
    • G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
    • G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
    • G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
    • G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
    • G11B5/3967—Composite structural arrangements of transducers, e.g. inductive write and magnetoresistive read

Definitions

  • the present invention relates to a magnetic head with high reluctance. It finds an application in the recording of information.
  • the invention applies essentially to so-called horizontal heads with thin layers. Such a head is shown in Figure 1 attached.
  • a head comprising a semiconductor substrate 10, for example made of silicon, in which a box 12 has been etched; in this box, a rear magnetic layer 14 has been formed electrolytically and has been extended by two vertical pillars 16 1 , 16 2 ; a coil 18 surrounds the pillars; this coil is embedded in an insulating layer 20.
  • the magnetic circuit is completed by a front magnetic piece comprising two pole pieces 22 1 , 22 2 separated by a non-magnetic spacer 24.
  • a magnetoresistive element MR is placed under the non-magnetic spacer 24.
  • the head moves in front of a magnetic support 30 where the information to be read or written is recorded.
  • the current flowing in the winding 18 creates a magnetic field and, consequently, an induction in the magnetic circuit.
  • the field lines which open out around the spacer induce a magnetization in the support 30.
  • magnetic information recorded in the support 30 produces a magnetic reading field and, consequently, an induction in the magnetic circuit; this induction closes, in part, through the magnetoresistive element MR. This results in a magnetization rotation in this element, which will cause a variation in its resistance.
  • Part of the magnetic flux is therefore unused in the reading step.
  • document FR-A-2 657 189 recommends opening the magnetic circuit so that the path (a) mentioned above is interrupted. The path (b) is then preferred. In practice, this document plans to remove the magnetic pillars 16 1 , 16 2 or even to remove the rear magnetic piece 14. But the write signal is very weakened by such disruption of the magnetic circuit.
  • Document EP-A-0 475 397 also proposes to open the magnetic circuit but in another way. He recommends carrying out an air gap (gap) in the rear magnetic part, or two auxiliary air gaps in the pillars while adding a second magnetic circuit used in reading and capable of reinforcing the flow directed towards the magnetoresistive element.
  • the object of the present invention is to remedy these drawbacks. It also recommends increasing the reluctance of the magnetic circuit but in a much simpler way.
  • the invention applies first of all to the heads which comprise, in addition to the means shown in FIG. 1, two flux concentrators arranged above the two pillars and magnetically coupled to the two pole pieces.
  • the invention therefore recommends separating these concentrators from the pole pieces by means of a non-magnetic layer.
  • a non-magnetic layer can be easily deposited during production, after the concentrators have been formed.
  • the magnetic decoupling thus caused eliminates many magnetic leaks which disturbed the operation of the front heads with auxiliary air gaps.
  • the present invention therefore relates to a magnetic head comprising a magnetic circuit with two magnetic concentrators and two pole pieces separated by a nonmagnetic spacer and a magnetoresistive element located under the nonmagnetic spacer, this head being characterized in that the two concentrators are separated from the two pole pieces by a nonmagnetic layer comprising at least one conductive layer.
  • the non-magnetic layer may have a thickness of between a fraction of a micrometer and a few micrometers.
  • the non-magnetic layer may consist of an insulating layer (in silica for example) covered with a conductive layer (in copper, chromium, tungsten, etc.).
  • the conductive layer will serve as an electrode in a step of electrolytic growth of the pole pieces.
  • the structure is well symmetrical and the read signal is also symmetrical.
  • FIGS. 3 to 6 show some sub-assemblies obtained during the production of a magnetic head according to the invention, the completed head being illustrated in FIG. 7.
  • FIG. 3 first of all, we see a first sub-assembly comprising, on a substrate 10, a rear magnetic piece 14, two pillars 16 1 and 16 2 , two concentrators 19 1 , 19 2 , a conductive winding 18 embedded in an insulator 20.
  • the shape of the concentrators is arbitrary, but the width of these parts towards the center of the head is narrower than at the level of the pillars.
  • a non-magnetic layer 30 is then deposited, as illustrated in FIG. 4, which, in the illustrated variant, comprises an insulating layer 32, for example made of silica, covered with a metallic layer 34, for example in tungsten.
  • a layer of resin or insulator 36 is deposited on the assembly (cf. FIG. 5) in which two boxes 38 1 and 38 2 are etched.
  • these boxes are filled by electrolytic growth, to obtain two magnetic pieces 40 1 , 40 2 as shown in FIG. 6.
  • the process then continues with operations well known to those skilled in the art: formation of a magnetoresistive element, formation of an insulating wall, growth of the pole pieces on either side of the wall.
  • the head finally obtained is shown in FIG. 7 with its two pole pieces 22 1 , 22 2 , separated by the non-magnetic spacer 24 and the magnetoresistive element MR. The latter is placed under the spacer, either under the pole pieces as illustrated, or between them.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Magnetic Heads (AREA)
EP97400295A 1996-03-19 1997-02-10 Magnetkopf mit starker Reluktanz Withdrawn EP0797188A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9603390 1996-03-19
FR9603390A FR2746572B1 (fr) 1996-03-19 1996-03-19 Tete magnetique a forte reluctance

Publications (1)

Publication Number Publication Date
EP0797188A1 true EP0797188A1 (de) 1997-09-24

Family

ID=9490302

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97400295A Withdrawn EP0797188A1 (de) 1996-03-19 1997-02-10 Magnetkopf mit starker Reluktanz

Country Status (4)

Country Link
US (1) US5764447A (de)
EP (1) EP0797188A1 (de)
JP (1) JPH1031809A (de)
FR (1) FR2746572B1 (de)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6762910B1 (en) 1999-06-03 2004-07-13 Western Digital (Fremont), Inc. Data storage and retrieval apparatus with thin film read head having inset extra gap insulation layer and method of fabrication
US6801408B1 (en) 2000-11-02 2004-10-05 Western Digital (Fremont), Inc. Data storage and retrieval apparatus with thin film read head having a planar sensor element and an extra gap and method of fabrication thereof
US6947256B2 (en) * 2003-01-29 2005-09-20 International Business Machines Corporation Embedded wire planar write head system and method

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0475397A2 (de) * 1990-09-12 1992-03-18 Sony Corporation Flächenförmiger dünnschichtiger Magnetkopf
EP0651374A2 (de) * 1993-11-01 1995-05-03 Hewlett-Packard Company Planarer magnetoresistiver Kopf
US5434733A (en) * 1994-02-18 1995-07-18 Hewlett-Packard Company Planar head having separate read and write gaps
EP0669607A2 (de) * 1994-02-28 1995-08-30 Read-Rite Corporation Magnetkopfzusammenbau mit MR-Sensor

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2724482B1 (fr) * 1994-09-13 1996-12-06 Commissariat Energie Atomique Tete magnetique a magnetoresistance multicouche longitudinale sous-jacente

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0475397A2 (de) * 1990-09-12 1992-03-18 Sony Corporation Flächenförmiger dünnschichtiger Magnetkopf
EP0651374A2 (de) * 1993-11-01 1995-05-03 Hewlett-Packard Company Planarer magnetoresistiver Kopf
US5434733A (en) * 1994-02-18 1995-07-18 Hewlett-Packard Company Planar head having separate read and write gaps
EP0669607A2 (de) * 1994-02-28 1995-08-30 Read-Rite Corporation Magnetkopfzusammenbau mit MR-Sensor

Also Published As

Publication number Publication date
JPH1031809A (ja) 1998-02-03
US5764447A (en) 1998-06-09
FR2746572B1 (fr) 1998-07-24
FR2746572A1 (fr) 1997-09-26

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